Electromagnetic device



Junels, 1959 .EUGON 2,891,199,l

ELECTROMAGNETIC DEVICE l FledJJan. 20, 1955 vvvvvvl 0.0.0900.

ATTO R N EY Uflited States Patent ELECTROMAGNETIC I )EVICE Pierre Eugne Ugon, Sceaux, France Application Jennery 2.0., 1955., Serial Nn: 4.8.3110! 8 Claims. (Cl. 3171-197):

The present invention relates to electromagnetic activating devices comprising an electromagnet associated with a movable armature and arranged so that energication of the magnet winding by an electric current produces movement of the armature due to magnetic attraction or repulsion and movement of the armature performs some additional electrical or vmehanical operation. For example, movement of the armature may control the opening or closing of switch contacts in an relectrical circuit, in which case the device operates as an eletrical relay, or alternatively movement of the armature may control some mechanical operation such as the locking Ofi releasing of a member.

It is an important object of the present invention to provide an improved forni of velectroniagneti; device of the above type for controlling electrical .or nieellnnll operations which is .of particularly compactl and eiiieient form and which enables eilcient miniature or Snbflnniaturc relays or other electro-magnetic control devices to be produced.

Another object .of .the invention .is .the provision of en electromagnetic device, such .es e relay, which, Wliie exhibiting ,a high response Sensitivity to .extremely Week energizing or exciting currents., is substantially .inseneitive to accelerating interfering ,forces such es meehenienl shock or vibration liable to cansennfiesiteble einerntinn .by .closing the relay contacts tor releasing .e controlled member, respectively.

.A more specic object is the provision of an electromagnetic device of `this type which, while being .eQInP-eel in construction and of ,small size and weight, c liablesall improved static .es well es magnetic balance ,ef its ennetnre to prevent operation .by .undesired vonteide forcee and to eliminate or rednce friction .on the' annetnte .0f bearing in such e manner as to insure te'SPOnSe sensitivity and operating satety thronghent lthe .life .ofthe device.

Ancillary objects and novel features lof the invention Vwill become apparent as the description of the v-specific embodiments proceeds, as Shown by the .accompanying drawings.

With the foregoing objects in view, ,anelectromagnetic device vaccording to the invention comprises `essentially a core of magnetic material .having associated ,therewith an exciting .coil `or winding adapted to be .energized by an electric current to -fcrrna snbetentiellycloseti electromagnetic circuit and an armature of soft iron .or the like mounted for rocking kmovement about an axis between ,two free and ,opposite poles ofsaid Icircuit I4 andbar langed to Aforni .a peri .of the Inngnetic Ipath of .Seid .circuiti euch a manner that, lwhen seid .coil .is energized. ,the Seid 4two Aopposite poles act on .portions of said arnlat'pre 4on opposite sides yof said vaxis with forces being equal and .opposite to .each .other .end et .right enelertn the/.ineen .nf s aid poles, thereby producinga couple 4acting onthearmal.ture to turn it about .said axis. lBy v.the .static as Vwell as magnetic balance .et .the nnnetnre, .which .tney .be .of .eX- tremely small weight, and proper biasing by a balance spring or the like, the moving parts are highly insensitive against outside accelerating forces, such as mechanical shock andvibration, thus preventing undesired operation of the 'relay or like device in Ypractically any position during use. v v

Preferably the armature, if in the form of a flat plate or strip, is pivoted about an axis passing through its cen'- ter of gravity, wh'erfehyvitV is normally ybalanced between the two" opposite polesof the electromagnet and thetvvo attractive forces produced `by the poles of the electromagnet and forming the couple are arranged so that no appreciable resultant transverse force is produced'onl the pivot on which the armature is mounted.

In o rder to further stabilize the armature and to reduce friction yof the armature axisor bearing, the 'latteiiis advantageously of an angular or V-'sha'pe pivoted vattire apex of the V', whereby at the'sarne time to reduce the sig/Le andrnounting space especially for relayscr other control devices designed for vuse in miniaturiz'ed electronic equipment. In the latter case, assuming aprop'er static balance of the armature, the axis atV the apex vof the and the center of gravity of the armatureiare within a plane bisecting the angle included by theopposite magnetic forces acting on the ends of the armature,'thereby resulting' in reduced friction moments on the armature axis due to the slight unbalance'of magnetic forces. According toa feature of the invention, the magnetic circuit totally'eneloses theY armature. i The iiventiori will be better understood from the following 'd'escription' of a VfewI practical embodiments', ltaken A .ith reference to the accompanying drawing vformingY part vof the specificati on'and'vvhereim v Y Figs. lY to 3 are diagrammatic elevational views, shown pantl'y in section, of a few practical embodiments of electromagnetic activating devices according lto the invention employing an armature in the form of a Hat strip dr plate;

` Figs. 4 and 5 show similar views of two embodiments of the invention employing a` bent or .V-shaped ;rmatre;

' 6 shows a modified form of a bent armature and an associated pole piece;v 'Y

Figs.v 7to 9fare`perspective views showing various lorrns of supports or suspension arrangement for a bent armature according to the invention;

Figs. l0 to l2 are fragmentary views showing, respec- .tiyely, three possible contact arrangements for anelectromagnetic relay associated with and having a bent armature according to the invention; and

Fig. 13 shows va diagrammatic View of a 4vcompleterelay construction according to the invention enclosed in a herrnetically sealed casing.

VLike reference characters identify like parts in the dif- .ferent views of the drawing.

v lleferririg more particularly to Fig. l, the devicevshown comprises a main or central core section 10 of magnetic material carrying an electric exciting vwinding or coil 1;1, ka lateral section or limb 12 adjoining the outside of Vsaid 'ridingV and a transverse section oryoke 13 terminating .a pole piece 14, to provide a substantially closed mag- `ticcircuit with the opposite or cooperating pole piecelS being constituted :by the Aend ,of the central core or ,section 1). The pole pieces 14 and 15 are so arranged as Sin to present a pair of laterally spaced parallel pele faces 10 the Opposite end ,surfaces of the soft iron armature sitivity or couple produced by the magnetic forces acting Within the air gaps between the armature and pole pieces if the winding 1 1 is excited by an energizing or control current. In other words, two very narrow and uniform air gaps separate the two ends of the armature 16 from the pole piece 15 on the free end of the core and the opposite or cooperating pole piece 14, respectively.

Figs. 2 and 3 show an alternative construction of a device according to the invention utilizing a straight armature plate similar to Fig. 1 but where tne entire relay structure including the winding 11 and armature 16 is embraced or enclosed by the magnetic circuit. For this purpose the central core section 10 is subdivided into two outer branches or limbs 12 and 12a adjoining the outer surfaces of the winding 11 and being united by the transverse section or yoke 13 in the manner shown. In this case the opposite or cooperating pole piece may have a different form, as shown in the drawing. In Fig. 2 the opposite pole piece 14a is constituted by a separate soft iron member mounted in the corner between the limb 12 and yoke 13, while in Fig. 3 the opposite pole piece is directly formed in or forms part of the yoke 13 of the magnetic circuit in the form of a step or shoulder 18 constituting an opposite pole equivalent to pole piece 14 of Fig. l and cooperating with the main pole 15.

A slight air gap such as in the form of a saw cut may be included in the magnetic circuit as indicated at 20 in Fig. 3, to facilitate the assembly of the energizing coil 11 on the core 10 by opening the lateral limbs 12 and 12a of the magnet core or circuit. The gap 20 in the magnetic circuit may also serve as a means for calibrating or finally adjusting the sensitivity and other characteristics of the device.

The magnetic circuit may be either solid, of cornpressed or powdered magnetic material such as iron, or laminated, but preferably iron laminations are employed. For example, a stack of laminations, of even number and being assembled in a direction within the plane of the drawing, about four times the length of the core 10 are held tightly together to form the core 10 and divided into tWo parts forming the limbs 12 and 12a which are bent to the desired shape, as shown more clearly in Fig. 5. In the latter, only two laminations are shown for ease of illustration. Alternatively, integral stampings having a shape corresponding to sections 10, 12 and 13 may be stacked in a direction at right angle to the plane of the drawing to obtain a laminated magnetic core in a manner readily understood.

The lateral branches 12 and 12a of the magnetic circuit and the poles 14a or 18 are arranged in a position relative to one another and to the armature 16 so as to exert forces on the armature which are as nearly as possible parallel to and equal to one another as well as at right angles to the pole faces in order to produce a maximum couple on the armature without any resultant force acting on the armature axis, provided the armature is statically balanced in the manner pointed out above. This insures that no or only small resultant forces are produced acting on the pivoting axis of the armature and causing frictional losses which may be serious particularly in small relays in reducing its sensitivity and shortening the life of the relays or equivalent devices. For practical purposes these resultant forces should be for example less than one-tenth of the largest forces acting between the movable armature and each of the poles.

The arrangement of Fig. 4 is distinguished from the previous arrangements by the form and construction of its movable armature 16 and the modilications relating to its magnetic circuit. According to this construction, the armature 16 is bent to a V shape to improve its static balance and to provide a device having two magnetic gaps that it is possible to adjust even after the parts have been assembled. If the relay is formed with two limbs or branches 12 and 12a as shown in Fig. 5, the core 10 is advantageously formed of an even num.- ber of sets of laminations which are divided between the two branches in the manner pointed out and shown in the drawing. fIf, on the contrary, the branch 12a is eliminated as is shown in Fig. 4, the two branches of the magnetic circuit remaining having the same number of laminations, which slightly facilitates the positioning of the energizing coil 11.

In Fig. 5 the device is shown in inverted position for mounting on a base member 22 provided with suitable connecting pins or prongs 23, to facilitate the connection to other electrical parts by insertion in a suitable base or socket, as is customary in the construction of electric equipment. In the construction of Fig. 5, the opposite magnetic pole is formed by the obiiquely bent portion 21 of the yoke 13, replacing the shoulder 18 of Fig. 3.

Fig. 6 is an enlarged view of a V-shaped armature provided with an extension 16a adapted to cooperate with a pole face, such as the pole presented by the core 10. In the constructions according to Figs. 4 and 5, the pole pieces co-operating with the V-shaped armature are advantageously provided with faces forming angles with the main core axis or branches of the magnetic circuit, to reduce both the mounting space required and to provide air gaps of minimum width as well as electric fields substantially at right angle to the faces of the poles. This, in turn, results in a maximum magnetic force and consequently in high response sensitivity of the relay for a given energizing current.

The reluctance of the gaps between the pole pieces and the armature 16 may be adjusted by varying the size of the pole pieces or armature or both, or by varying the width of the air gaps in the normal or rest position, in an eiiort to control and adjust the sensitivity and magnetic balance of the armature. Thus the size of the gap between the pole 15 close to the magnet winding of the core 10 and the armature 16 is shown to be less Vthan the size of the gap between the outer magnet pole 14a and the armature, to compensate for the reduced magnetic force in said last gap due to the existence of magnetic stray ux or leakage. Similarly, in Figs. 5 and 1() to 13, the size of the gap between the pole 15 and one half of the V-shaped armature 16 is shown to be of lesser size than the gap between the magnet pole 21 and the other half of the armature 16, to produce opposite and balanced magnetic forces on said armature.

The armature 16 may be suitably biased in a manner well known, such las by constructing it of resilient material or by the provision of a spiral or helical balancing spring or equivalent biasing means, as shown at 24 in Figs. 5 and 6, to provide a control or balancing force or moment restoring the armature to neutral position in the non-excited condition of the relay and insuring uni form and consistent operation of the relay or equivalent actuating device. In other words, the spring 24 or equivalent biasing member normally keeps the armature oi the pole pieces 14 and 15 and may be adjustably tensioned by an adjusting screw or the like. For practical purposes, the angle of the V may be about in which case the angles formed by the pole pieces will be about 45. However, any other angle substantially differing from 90 may be used to suit existing requirements and conditions.

The bent or V-shape of the armature, aside from reducing the space and improving the compactness of the device, has the further advantage of enabling the use of an armature of extremely light weight and insuring a better static balance of the armature and to reduce the friction `on the armature axis. This lrenders the device less sensitive to outside interference or accelerating forces, such as vibration. Furthermore, the V-shape of the armature, while producing the same magnetic eld and attractive and repulsive forces on the opposite ends of the armature, has the effect of greatly reducing the reacting moments on the armature axis, thus minimizing friction `and enabling the devices to be manufactured with less strict tolerance requirements with Vrespect to static as well as magnetic armature balance. This in turn results in greater uniformity in quantity production and a reduced number of rejects or defective units in manufacture and in use.

Figs. 7 to 9 are perspective views showing mounting -arrangements for the V-Shaped armature 16 fixed on shaft 17, the latter being in turn mounted in bearings in a supporting frame 25. This frame is preferably resilient and elastic and may be slotted as shown in Fig. 8 or provided with an extension as shown in Fig. 9, in order to insure that the frame forms an antishock support for the pivot 17 and armature 16.

Though the armature is located within the magnetic circuit, it may have to operate contacts outside the circuit, as shown in Fig. lO, where a conducting finger 26 .attached to the armature 16 engages either of two fixed contacts 27 and 2S through a narrow opening 29 in lthe yoke 13. The finger 26 is preferably made as light .as possible in order to keep the additional Iweight and .inertia of the armature to a minimum and to allow .rapid movement of the armature which is particularly desirable in miniature relays. `erating contacts, the finger 26 may perform some melf desired, instead of op- -chanical control, such as a latching or unlatching action, or control an escapement.

lf the contact assembly 26, 27, 28 is arranged inside the yoke 13 or magnetic circuit, the conductors leading to the contacts may pass through the top of the relay, Fig. 11, or the base, Fig. l2, as may be desired.

A preferred embodiment of relay constructed according to the invention is `shown in Fig. 13. The relay shown which may be hermetically sealed and tropicalized employs the arrangement of Fig. 5 and the contact assembly shown in Fig. ll. The whole is housed inside a hermetic casing 30 and an insulating support 22, for example of steatite or any other suitable insulating plastic, is provided for mounting the relay and for the passage of the connecting leads. These leads are secured to connecting pins or prongs 26', 27', and 31 mounted in an insulating base 32 of glass, for example, of which the periphery 34 is sealed hermetically to the casing 30. The armature 16 is shown biased by a spiral balancing spring 35 to return it to neutral position in the unexcited condition of the relay winding and to control or countervact the magnetic attractive forces upon energization of the winding by a control current or pulse.

The number of connecting pins or prongs on the insulating base 32 depends upon the construction of the relay and the number of contacts provided. Preferably the pins are spaced and -arranged so that they will fit in conventional tube sockets or other holders, whereby the relay may be simply plugged in to its associated circuit. Fig. 13 only shows some of the pins, notably those which are joined to the fixed contacts 27 and 2S :of the relay. The other may be connected in various manners depending on the design and specific use of the relay.

The characteristics of the devices according to the invention are not only applicable to the construction of miniature or sub-miniature relays, for they provide advantages when the device is not miniaturized and one may apply the invention to switches, circuit breakers and more generally any protection or control device operating either by the simple or multiple closing or breaking of electrical circuits or by direct mechanical action or control.

In the foregoing the invention has been described with reference to a few illustrative devices. It will be evident, however, that variations and modifications, as well as the substitution of equivalent elements for those shown may be made without departing from the broader 6 scope of the invention as defined in the appended claims. The specification and drawing are accordingly to be regarded in an illustrative rather than in a limiting sense.

I claim:

1. An electromagnetic device comprising a core of magnetic material shaped to provide a substantially closed magnetic circuit with two exposed poles of said circuit having opposed faces at angles with the core axis and being parallel to and laterally spaced from one another, an exciting winding upon said core closely adjoininfy one of said poles, and an armature pivotally mounted in statically balanced condition between said poles about a fixed central axis, said armature having opposite end faces opposed each by one of said pole faces, to provide a pair of substantially uniform air gaps, the air gap adjacent to the pole adjoining said winding having a lesser effective cross-sectional area than the air gap adjacent to the other of said poles, to cause substantially equal and opposite magnetic forces on said armature creating a couple, to rotate the same about said axis.

2. An electromagnetic device comprising a core of magnetic material shaped to provide a substantially closed ma-gnetic circuit ywith two exposed poles of said circuit having opposed faces at right angles to the core axis and being parallel to and laterally spaced from one another, an exciting winding upon said core closely adjoining one of said poles, and an armature pivotally mounted in statically balanced condition between said poles about a fixed central axis, said armature having its opposite end faces opposed each by one of said pole faces, to provide a pair of substantially uniform air gaps, the air gap adjacent to the pole adjoining said winding having a lesser effective cross-sectional area than the air gap adjacent to the other of said poles, to cause substantially equal and opposite magnetic forces on said armature creating a couple, to rotate the same about said axis.

3. An electromagnetic device comprising a core of magnetic material shaped to provide a substantially closed magnetic circuit with two exposed poles of said circuit having opposed faces forming acute angles withl the core axis and spaced laterally from and including an angle with one another, an exciting winding upon said core closely adjoining one of said poles, and a V- shaped armature pivotally mounted in statically balanced condition between said poles about an axis at the apex of the V, said armature having its opposite end faces opposed each by one of said pole faces, to provide a pair of substantially uniform magnetic air gaps, the air gap adjacent to the pole adjoining said winding having a lesser effective cross-sectional area than the air gap adjacent to the other of said poles to cause substantially equal and opposite magnetic forces on said armature creating a couple, to rotate the same about said axis.

4. An electromagnetic device comprising a core of magnetic material shaped to provide a substantially closed magnetic circuit with two exposed poles of said circuit having opposed faces forming equal acute angles with the core axis and spaced laterally from and including an angle with one another, an exciting winding upon Said core closely adjoining one of said poles, and a V-shaped armature pi-votally mounted in statically balanced condition between said poles about a fixed axis at the apex of the V, said armature having opposite end surfaces opposed each by one of said pole faces, to provide a pair of substantially uniform air gaps, the gap adjacent to the pole adjoining said winding having a lesser effective cross-sectional area than the air gap adjacent to the other of said poles to cause substantially equal and opposite magnetic forces on said armature creating a couple, to rotate the same about said axis.

5. An electromagnetic device comprising a core of magnetic material shaped to provide a Substantially closed magnetic circuit with two exposed poles of said circuit having opposed faces at angles to the core axis and spaced laterally from one another, an exciting winding upon said core closely adjoining one of said poles, and 'an armature pivotally mounted in statically balanced condition between said poles about a fixed central axis, said armature having it opposite end surfaces opposed each by one of said pole faces, to provide a pair of substantially uniform air gaps, the air gap adjacent to the pole adjoining said winding having a lesser effective cross-sectional area than the air gap adjacent to the other of said poles, to cause `substantially equal and opposite magnetic forces on said armature creating a couple, to rotate the same about said axis.

6. An electromagnetic device comprising a core of magnetic material having a Central portion terminating in a first pole face including an angle with the core axis, a pair of lateral branches extending from said central portion, one of said branches having a portion presenting a further pole face including an angle with said first pole face, an exciting winding upon said central portion closely adjoining said first pole face, and a V-shaped armature pivotally mounted in statically balanced condition between said pole faces about a fixed axis at the apex of the V, said armature having its opposite end faces each opposed by one of said pole faces, to provide a pair of substantially uniform magnetic air gaps, the air gap adjacent to said first pole face having a lesser effective cross-sectional area than the air gap adjacent to said further pole face to cause substantially equal and opposite magnetic forces on said armature creating a couple, to rotate the same about said axis.

7. An electromagnetic device comprising a core of magnetic material having a central portion terminating in a first pole face including a 45 angle with a core axis, a pair of lateral branches extending from said central portion, one of said branches having a portion presenting a further pole face including a right angle with said first pole face, an exciting winding upon said central portion closely adjoining said first pole face, and a rectangular V-shaped armature pivotally mounted in statically balanced condition between said pole faces about a fixed axis at the apex of the V, said armature having its opposite end faces each opposed by one of said pole faces, to provide a pair of substantially uniform magnetic air gaps, the air gap adjacent to said rst pole face having a lesser effective cross-sectional area than the air :gap adjacent to said further pole face to cause substantially equal and opposite magnetic forces `on said armature creating a couple, to rotate the same about said axis.

8. An electromagnetic device comprising a core of magnetic material bent to provide a substantially closed magnetic circuit with two pole surfaces of opposite polarity llaterally spaced from one another, an exciting winding upon said core close to one of said surfaces, and an armature pivotally mounted in statically balanced condition between said pole surfaces about a central axis, said armature having its end faces opposed each by one of said pole surfaces, to provide a pair of magnetic air gaps of different effective cross-sectional areas to cause opposite and substantially balanced magnetic forces on said arma-ture, substantially independently of magnetic leakage weakening the magnetic ux through the other of said pole surfaces, to create a couple and to rotate said armature about said axis.

References Cited in the le of this patent UNITED STATES PATENTS 1,763,008 Priessman June l0, 1930 1,852,232 Buchhold Apr. 5, 1932 2,455,049 Edwards et al. Nov. 30, 1948 FOREIGN PATENTS 410,690 Italy Apr. 20, 1945 949,797 France Sept. 8, 1949 1,054,324 France Oct. 7, 1953 

